CN111535162A - Energy dissipation and shock absorption device for improving shock resistance of prefabricated assembled concrete filled steel tube pier - Google Patents

Abstract

The invention discloses an energy dissipation and shock absorption device for improving shock resistance of a segment-assembled concrete-filled steel tube pier, and belongs to the field of bridge engineering construction. The invention improves the energy consumption of the section-assembled concrete-filled steel tube pier, enhances the connection between the sections of the pier, can reduce the displacement of the pier top by coordinating the stress deformation between the sections in the earthquake, only needs to replace the damaged pull rod in time after the earthquake, and has good repairability after the earthquake.

Description

An energy dissipation and shock absorption device for improving the seismic resistance of prefabricated concrete-filled steel tube piers

Technical Field The present invention belongs to the field of bridge engineering, and in particular relates to an energy dissipation and shock absorption device for improving the seismic resistance of prefabricated and assembled concrete-filled steel tubular bridge piers.

Background Art Prefabricated reinforced concrete bridge piers are currently mostly used on highway bridges and canal bridges in low-intensity areas, because these projects have high requirements on construction environment and construction period, and can give full play to the advantages of factory prefabrication. The shortcomings of the joints at the bottom of the segmental assembled bridge piers during earthquakes are severe damage, poor energy dissipation, and high displacement requirements at the top of the piers, which limit its popularization in areas with medium and high intensity. The larger displacement of the pier top puts forward higher requirements for the design of the anti-falling beam of the superstructure of this type of bridge pier.

With the improvement of inter-segmental connection and assembly technology, some prefabricated pier structures with high vertical bearing capacity of piers and suitable for high-intensity areas have been proposed and studied. The use of steel tube to confine concrete can greatly improve the axial bearing capacity of the member. At the same time, due to the good ductility of steel, CFST piers not only have high bearing capacity, but also have good horizontal bearing capacity. During the processing of prefabricated components, the steel pipe can be used as the lateral formwork of concrete at the same time, which can improve work efficiency and is economical.

Compared with the integral cast-in-place piers, the prefabricated concrete-filled steel tubular piers have lower energy dissipation under earthquake action, and additional energy dissipation devices are needed to improve them. At present, the energy dissipation devices developed for prefabricated piers in China are mainly divided into three categories: internal energy dissipation devices, such as setting energy dissipation steel bars inside the joints of segmental piers; external energy dissipation devices, such as external energy dissipation devices at the joints of segmental piers Install dampers or mild steel dampers; pier bottom energy dissipation devices, such as energy dissipation supports at the connection between the pier bottom and the bearing platform. Existing energy-consuming and shock-absorbing devices have their own advantages and disadvantages, and internal energy-consuming devices have poor repairability after earthquakes. Therefore, external energy-consuming devices can be the first choice for design under the premise of good durability.

In recent years, the seismic design of structures has increasingly focused on performance-based design methods. It is hoped that through reasonable and ingenious design, the structures have post-earthquake recovery performance to minimize the economic losses caused by earthquakes. Prestressed segmental prefabricated piers have been extensively studied abroad and have been widely used in low-intensity areas. The pier segments are integrated through prestressed axial connections, and the prestressing provides bearing capacity and self-reset capability; prestressing The response of segmental prefabricated piers under the action of earthquake can be likened to a tumbler swaying structure. When the bending moment generated by the external load reaches the resisting moment provided by the self-weight and prestress of the structure, the pier begins to rotate around the pier bottom. The joint of the contact part between the pier bottom and the foundation opens and closes. The installation of energy dissipation devices at the joint of the pier bottom and the joints of adjacent pier segments can effectively dissipate the seismic energy and reduce the damage of the structure itself. Since the opening of joints between segments under the action of the earthquake will cause a large displacement of the top of the pier, when developing the external energy dissipation device, it is necessary to ensure that there will be no additional residual displacement due to its own buckling deformation after the earthquake. Ability to deform at seams. At present, the external energy dissipation devices proposed at home and abroad have the problems that large additional residual displacements are generated, their own rigidity is not enough to control the deformation of the joints, and the effect of energy dissipation and shock absorption is not obvious.

SUMMARY OF THE INVENTION In order to solve the above problems, the purpose of the present invention is to provide an energy dissipation method that is convenient for construction, has no additional residual displacement, and can be repaired after an earthquake, and at the same time can effectively control the deformation of the joints to improve the seismic performance of prefabricated concrete-filled steel tubular piers. Shock Absorber.

The technical scheme adopted in the present invention is as follows:

An energy dissipation and shock absorption device for improving the seismic resistance of a prefabricated and assembled concrete-filled steel tube pier, comprising a first load-bearing top plate, a foot plate, a second load-bearing top plate, a load-bearing bottom plate and a tie rod; the first load-bearing top plate and the load-bearing bottom plate and the first steel tube concrete segment are mutually Vertically fixed, the second load-bearing top plate and the second steel tube concrete section are vertically fixed to each other, between the first load-bearing top plate and the foot plate, and between the second load-bearing top plate and the load-bearing bottom plate, all pull rods, the upper end of the tie rod is welded to the base, and the upper end of the tie rod passes through the base They are respectively connected with the first load-bearing top plate and the second load-bearing top plate, the lower ends of the tie rods are respectively connected with the foot plate threadedly, connected with the load-bearing bottom plate and fixed by nuts; the foot plate is fixed with the bearing platform through the anchor bolts.

The first CFST segment, the second CFST segment, and the third CFST segment are circular steel pipes or rectangular steel pipes, PVC pipes are fixed in the center of the steel pipes, prestressed tendons are installed in the PVC pipes, and there are spaces between the inside of the steel pipes and the outside of the PVC pipes. Concrete is poured inside, the lower ends of the prestressed tendons are anchored in the cap via anchors, and the prestressed tendons pass through the PVC pipes in the first CFST segment, the second CFST segment, and the third CFST segment, respectively. The upper end of the rib and the pier cap are anchored by anchors.

The thickness of the first load-bearing top plate, the foot plate, the second load-bearing top plate and the load-bearing bottom plate is not less than the maximum diameter of the tie rod.

The first load-bearing top plate, the load-bearing bottom plate and the first concrete-filled steel tube segment are welded and fixed perpendicular to each other, and the second load-bearing top plate and the second concrete-filled steel tube segment are welded and fixed perpendicular to each other, and the welding method adopts full penetration weld connection.

The diameter of the first load-bearing top plate, the second load-bearing top plate and the load-bearing bottom plate is 4mm-5mm larger than the diameter of the tie rod hole, and the diameter of the upper end base of the tie rod is 3cm-4cm larger than the diameter of the reserved tie rod hole.

The tie rods are made of ordinary steel bars, high-strength steel bars or shape memory alloys, and the outside of the tie rods is wrapped with a layer of polytetrafluoroethylene anti-corrosion material or other materials with small friction coefficients.

The advantages of the present invention are:

The construction is convenient, the deformation restriction between the CFST segments is obvious, and the energy dissipation of the CFST segment piers can be improved. The damaged tie rods can be replaced in time after the earthquake, which has good repairability and will not bring additional damage. The residual displacement after the earthquake is mainly reflected in:

1. During an earthquake, when the load-bearing top plate and the load-bearing bottom plate rotate relative to the adjacent concrete-filled steel tubular segments, the rotating outer tie rods limit the opening of the joint by bearing the tensile force, and the tensile force is mainly provided by its axial stiffness. The structural characteristics of the bolt joint are not under pressure, so there is basically no residual displacement after the earthquake caused by the buckling deformation of the tie rod. After the earthquake, it is only necessary to replace the damaged tie rod in time, which has good repairability after the earthquake;

2. The relative rotation between adjacent CFST segments is very small, and there is no bending of the tie rod during rotation, so there is basically no phenomenon that the tie rod is stuck with the load-bearing plate after bending. When the relative dislocation of the adjacent CFST segments may occur, all the tie rods participate in the work to become shear members, which can improve the shear bearing capacity of the CFST piers;

3. During the earthquake, the tie rod itself produces elastic-plastic deformation in the process of suppressing the deformation between the CFST segments to consume the seismic energy without the occurrence of buckling, which not only improves the energy dissipation of the structure, but also reduces the displacement demand of the pier top ;

4. The material of the tie rods can be conveniently and flexibly selected from ordinary steel bars, high-strength steel bars or shape memory alloys, etc. By changing the length, quantity and diameter of the tie rods to adjust the limit effect of the tie rods on the CFST segments, the energy consumption of the structure can be adjusted. pier top displacement during earthquakes;

5. The construction of the load-bearing plate is convenient. It only needs to be welded at the corresponding position of the concrete-filled steel tube segment. The construction method is mature and the economy is strong.

Brief Description of the Drawings Fig. 1 is a schematic diagram of the application of the tie rod energy dissipation and shock absorption device of the present invention;

Figure 2(a) is an A-A sectional view of a CFST bridge pier segment;

Figure 2(b) is another A-A sectional view of the CFST bridge pier segment;

Fig. 3 is the front view of the structure of the tie rod energy dissipation damping device of the present invention;

Figure 4(a) is a top view of a structure of the tie rod energy dissipation damping device of the present invention;

Figure 4(b) is a top view of another structure of the tie rod energy dissipation damping device of the present invention;

In the picture: 1. The first load-bearing top plate, 2. The load-bearing bottom plate, 3. The base, 4. The PVC pipe, 5. The prestressed tendons, 6. The anchors, 7. The pier cap, 8. The third CFST segment, 9. , the second CFST segment, 10, the second load-bearing top plate, 11, the nut, 12, the first CFST segment, 13, the tie rod, 14, the foot plate; 15, the bearing platform, 16, the anchor bolt.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be further described below with reference to the accompanying drawings.

As shown in Figures 1, 3 and 4, an energy dissipation and shock absorption device for improving the seismic resistance of prefabricated concrete-filled steel tubular piers includes a first load-bearing top plate 1, a foot plate 14, a second load-bearing top plate 10, a load-bearing bottom plate 2 and a tie rod 13; The first load-bearing top plate 1 and the load-bearing bottom plate 2 and the first concrete-filled steel tubular segment 12 are vertically fixed to each other, and the second load-bearing top plate 10 and the second concrete-filled steel tubular segment 9 are vertically fixed to each other, between the first load-bearing roof 1 and the foot plate 14. Between the second load-bearing top plate 10 and the load-bearing bottom plate 2, a rod 13 is drawn, the upper end of the pull rod 13 is welded with the base 3, and the upper end of the pull rod 13 is connected with the first load-bearing top plate 1 and the second load-bearing top plate 10 respectively through the base 3, and the lower end of the pull rod 13 is respectively It is screwed with the foot plate 14 , connected with the load-bearing bottom plate 2 and fixed by the nut 11 ; the foot plate 14 is fixed with the bearing platform 15 by the anchor bolt 16 .

As shown in FIG. 2 , the first CFST segment 12 , the second CFST segment 9 , and the third CFST segment 8 are circular steel pipes or rectangular steel pipes. Install the prestressed tendon 5, pour concrete inside the steel pipe and the outer space of the PVC pipe 4, the lower end of the prestressed tendon 5 is anchored in the cap 15 through the anchor 6, and the prestressed tendon 5 passes through the first concrete-filled steel tubular segment 12, the second The PVC pipe 4 in the second CFST segment 9 and the third CFST segment 8 , the upper end of the prestressed tendon 5 and the pier cap 7 are anchored by anchors 6 .

The thickness of the first load-bearing top plate 1 , the foot plate 14 , the second load-bearing top plate 10 and the load-bearing bottom plate 2 is not less than the maximum diameter of the tie rod 13 .

The first load-bearing top plate 1, the load-bearing bottom plate 2 and the first concrete-filled steel tube segment 12 are welded and fixed perpendicular to each other, and the second load-bearing top plate 10 and the second concrete-filled steel tube segment 9 are welded and fixed perpendicular to each other, and the welding method adopts full penetration weld connection. , so as to ensure that the axial force of the pull rod 13 can be transmitted reliably.

The diameter of the first load-bearing top plate 1, the second load-bearing top plate 10 and the load-bearing bottom plate 2 is 4mm-5mm larger than the diameter of the tie rod 13, and the diameter of the upper base 3 of the tie rod 13 is 3cm-4cm larger than the diameter of the tie rod 13.

The tie rod 13 is made of ordinary steel bars, high-strength steel bars or shape memory alloys, etc. The tie rod 13 is wrapped with a layer of PTFE anti-corrosion material or other materials with a small friction coefficient to ensure that the tie rod 13 passes through the first load-bearing top plate when it is under pressure. 1. The second load-bearing top plate 10 and the load-bearing bottom plate 2 slide relative to each other without being pressed, and at the same time, the durability of the tie rod 13 can be ensured.

According to the present invention, the foot plate 14 is manufactured in the factory according to the size of the bearing platform 15, and the tie rod 13 hole is reserved at the corresponding position in the center of the foot plate 14. According to the design requirements, the corresponding type of high-strength steel bar or ordinary steel bar or shape memory alloy and other materials are selected as the tie rod 13 and processed into a bolt shape. There are vertical distances between the second load-bearing top plate 10 and the load-bearing bottom plate 2 and between the first load-bearing top plate 1 and the foot plates 14 , and the size of the distance is determined by the length of the tie rod 13 . The center of the reserved tie rod hole in the first load-bearing top plate 1 and the center of the corresponding reserved tie rod hole in the foot plate 14 are on the same vertical line, and the center of the reserved tie rod hole in the second load-bearing top plate 10 is on the same vertical line as the corresponding reserved tie rod hole in the load-bearing bottom plate 2. Keep the center of the tie rod hole on the same vertical line. The bearing platform 15 is cast and cured on site according to the actual design size during construction. The foot plate 14 is made in the factory with the same size and shape as the top surface of the bearing platform 15, and the inner thread hole of the tie rod 13 and the hole channel of the anchor bolt 7 are accurately reserved.

Claims (6)

1. An energy dissipation and shock absorption device for improving the seismic resistance of prefabricated and assembled concrete-filled steel tubular piers, characterized in that: comprising a first load-bearing top plate (1), a foot plate (14), a second load-bearing top plate (10), and a load-bearing bottom plate (2) and tie rods (13); the first load-bearing top plate (1) and the load-bearing bottom plate (2) and the first concrete-filled steel tubular segment (12) are vertically fixed to each other, and the second load-bearing top plate (10) and the second concrete-filled steel tubular segment (9) They are fixed vertically to each other, and between the first load-bearing top plate (1) and the foot plate (14), and between the second load-bearing top plate (10) and the load-bearing bottom plate (2), all pull rods (13), and the upper end of the pull rod (13) is welded to the base ( 3), the upper end of the pull rod (13) is connected with the first load-bearing top plate (1) and the second load-bearing top plate (10) through the base (3), respectively, and the lower end of the pull rod (13) is screwed with the foot plate (14) and connected with the load-bearing bottom plate (10). 2) Connected and fixed by the nut (11); the foot plate (14) is fixed with the bearing platform (15) by the anchor bolt (16). 2. A kind of energy dissipation and shock absorption device for improving the seismic resistance of prefabricated CFST bridge piers as claimed in claim 1, characterized in that: the first CFST segment (12), the second CFST segment (9), The third CFST segment (8) is a circular steel pipe or a rectangular steel pipe, a PVC pipe (4) is fixed in the center of the steel pipe, a prestressing rib (5) is installed in the PVC pipe (4), and the interior of the steel pipe is spaced from the outside of the PVC pipe (4). Concrete is poured inside, the lower ends of the prestressed tendons (5) are anchored in the bearing platform (15) by means of anchors (6), and the prestressed tendons (5) respectively pass through the first concrete-filled steel tubular segment (12) and the second concrete-filled steel tubular segment. The PVC pipe (4) in the segment (9) and the third CFST segment (8), the upper end of the prestressed tendon (5) and the pier cap (7) are anchored by means of anchors (6). 3. A kind of energy dissipation and shock absorption device for improving the seismic resistance of prefabricated concrete-filled steel tubular piers as claimed in claim 1, characterized in that: the first load-bearing top plate (1), the foot plate (14), the second load-bearing top plate ( 10) The thickness of the load-bearing bottom plate (2) is not less than the maximum diameter of the tie rod (13). 4. The energy dissipation and shock absorption device for improving the seismic resistance of prefabricated CFST bridge piers according to claim 1, characterized in that: the first load-bearing top plate (1), the load-bearing bottom plate (2) and the first steel tube concrete The segments (12) are welded and fixed perpendicular to each other, the second load-bearing top plate (10) and the second concrete-filled steel tubular segment (9) are welded and fixed perpendicular to each other, and the welding method adopts full penetration weld connection. 5. The energy-dissipating and shock-absorbing device for improving the seismic resistance of prefabricated concrete-filled steel tubular piers according to claim 1, characterized in that: the first load-bearing top plate (1), the second load-bearing top plate (10) and the load-bearing bottom plate (2) The diameter of the hole of the reserved tie rod (13) is 4mm-5mm larger than the diameter of the tie rod (13), and the diameter of the upper base (3) of the tie rod (13) is 3cm-4cm larger than the diameter of the hole of the reserved tie rod (13). 6 . The energy-dissipating and shock-absorbing device for improving the seismic resistance of prefabricated CFST bridge piers according to claim 1 , wherein the tie rods ( 13 ) are ordinary steel bars, high-strength steel bars or shape memory alloys. 7 .

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